The German government is very concerned that there is still no comprehensive ceasefire in eastern Ukraine, more than a week after it should have taken effect, and urged Moscow anew on Monday to use its influence over pro-Russian separatists.

"When you look at the situation as a whole since leaders met in Minsk, it is clear the implementation of the agreed measures is not satisfactory," said government spokesman Steffen Seibert.

"What is decisive is a comprehensive cease fire. It is worrying for the German government that we haven't seen anything like this yet," he said.

A spokesman for the German foreign ministry urged Russia to free Ukrainian pilot Nadezhda Savchenko, who has been on hunger strike since last December and was visited by German doctors.